/**
 * 判断日期是否在区间内，在区间内返回true，否返回false
 * @param dateString 日期字符串
 * @param startDateString 区间开始日期字符串
 * @param endDateString 区间结束日期字符串
 * @returns {Number}
 */
function isDateBetween(dateString, startDateString, endDateString){
    var flag = false;
    if (isNotEmpty(dateString) && isNotEmpty(startDateString) && isNotEmpty(endDateString)){
        var startFlag = (dateCompare(dateString, startDateString) < 1 );
        var endFlag = (dateCompare(dateString, endDateString) ===1);
        if((startFlag && endFlag)){
            flag = true;
        }
    }
    return flag;
}
